This study assessed the influence of acquisition parameters of tomographic volumes on the reproduction of thin bone structures for rapid prototyping purposes. Two parameters were investigated: Field of View (FOV) and ...This study assessed the influence of acquisition parameters of tomographic volumes on the reproduction of thin bone structures for rapid prototyping purposes. Two parameters were investigated: Field of View (FOV) and Slice Thickness (ST). The specimen was comprised of five pairs of 0.6 mm, 1.1 mm, 1.5 mm, 2.0 mm and 2.8 mm thick cortical bone plates. The plates were stuck into utility wax;the first plate of the pair was in vertical position while the second plate was oblique to the first one. Forty-five tomographic images were captured and separated into 3 groups of fifteen images. Each group had a specific FOV: 180 mm;250 mm and 430 mm, respectively. Within each of these three groups, tomographic slice thickness was varied for every five of the fifteen slices. Acquisitions were carried out with STs of 1 mm, 2.5 mm and 5 mm. The Cyclops Medical Station software was used in the voxel-to-voxel analysis of radiologic density, reaching a total of 1350 assessed images. ST and FOV variation influenced the reproduction of thin bone walls, and FOV was shown to be a very important parameter. The larger the acquisition FOV, the more reduction in the number of voxels within the range of reconstruction for cortical bone in all of the bone plates. The visual analysis of the images of very thin bone walls showed that there could be a sharp drop in the radiologic density value in several adjacent voxels, resulting in areas which might not be reproduced in the reconstruction.展开更多
In this paper,an irregular displacement-based lensless wide-field microscopy imaging platform is presented by combining digital in-line holography and computational pixel super-resolution using multi-frame processing....In this paper,an irregular displacement-based lensless wide-field microscopy imaging platform is presented by combining digital in-line holography and computational pixel super-resolution using multi-frame processing.The samples are illuminated by a nearly coherent illumination system,where the hologram shadows are projected into a complementary metal-oxide semiconductor-based imaging sensor.To increase the resolution,a multi-frame pixel resolution approach is employed to produce a single holographic image from multiple frame observations of the scene,with small planar displacements.Displacements are resolved by a hybrid approach:(i)alignment of the LR images by a fast feature-based registration method,and(ii)fine adjustment of the sub-pixel information using a continuous optimization approach designed to find the global optimum solution.Numerical method for phase-retrieval is applied to decode the signal and reconstruct the morphological details of the analyzed sample.The presented approach was evaluated with various biological samples including sperm and platelets,whose dimensions are in the order of a few microns.The obtained results demonstrate a spatial resolution of 1.55 μm on a field-of-view of<30 mm^(2).展开更多
基金funded by a grant from FUNPESQUISA-Federal University of Santa Catarina.
文摘This study assessed the influence of acquisition parameters of tomographic volumes on the reproduction of thin bone structures for rapid prototyping purposes. Two parameters were investigated: Field of View (FOV) and Slice Thickness (ST). The specimen was comprised of five pairs of 0.6 mm, 1.1 mm, 1.5 mm, 2.0 mm and 2.8 mm thick cortical bone plates. The plates were stuck into utility wax;the first plate of the pair was in vertical position while the second plate was oblique to the first one. Forty-five tomographic images were captured and separated into 3 groups of fifteen images. Each group had a specific FOV: 180 mm;250 mm and 430 mm, respectively. Within each of these three groups, tomographic slice thickness was varied for every five of the fifteen slices. Acquisitions were carried out with STs of 1 mm, 2.5 mm and 5 mm. The Cyclops Medical Station software was used in the voxel-to-voxel analysis of radiologic density, reaching a total of 1350 assessed images. ST and FOV variation influenced the reproduction of thin bone walls, and FOV was shown to be a very important parameter. The larger the acquisition FOV, the more reduction in the number of voxels within the range of reconstruction for cortical bone in all of the bone plates. The visual analysis of the images of very thin bone walls showed that there could be a sharp drop in the radiologic density value in several adjacent voxels, resulting in areas which might not be reproduced in the reconstruction.
基金We would like to acknowledge National Institute of Health(NIH)NIH R01AI093282,NIH R01AI081534,NIH U54EB15408,NIH R21AI087107,and Brigham and Women’s Hospital-BRI Translatable Technologies and Care Innovation GrantWe would also like to acknowledge the support provided by the Brazilian National Council for Scientific and Technological Development(process 551967/2011-0)
文摘In this paper,an irregular displacement-based lensless wide-field microscopy imaging platform is presented by combining digital in-line holography and computational pixel super-resolution using multi-frame processing.The samples are illuminated by a nearly coherent illumination system,where the hologram shadows are projected into a complementary metal-oxide semiconductor-based imaging sensor.To increase the resolution,a multi-frame pixel resolution approach is employed to produce a single holographic image from multiple frame observations of the scene,with small planar displacements.Displacements are resolved by a hybrid approach:(i)alignment of the LR images by a fast feature-based registration method,and(ii)fine adjustment of the sub-pixel information using a continuous optimization approach designed to find the global optimum solution.Numerical method for phase-retrieval is applied to decode the signal and reconstruct the morphological details of the analyzed sample.The presented approach was evaluated with various biological samples including sperm and platelets,whose dimensions are in the order of a few microns.The obtained results demonstrate a spatial resolution of 1.55 μm on a field-of-view of<30 mm^(2).